LBJ passed away 1/22/73. I'm can try and help...where did your mom and dad live when the show air? There's some resources I can try and find via old TV Guides, trying to pinpoint if it was a Barker or Dennis James episode.
The location is important because the nighttime show was in a special television situation called "checkerboard syndication". This basically means that a show was syndicated (bought by one channel in a market to air) only once a week, unlike syndication today, which is 5 day a week strips. Also, due to a specific system in place called bicycling, not every station aired the same program.
In essence, your mom's episode may have aired 1/22/73 in that area, and possibly months later (or earlier) in my area because of this system.
Dennis James hosted the nighttime show from 1972-1977, to which Bob took over until the run ended in 1980.
(Hope I didn't confuse you too much!)